IPv6 seems to be a great fit for 1) mobile devices, 2) massive data centers and 3) literally nothing else.

I have met zero network engineers who wanted to put IP version 6 in their network. It causes all sorts of problems and presents all sorts of security risks without much benefit other than the obvious one. In the data center, NAT is a feature, not a bug.

Instead, they provision IPv6-enabled load balancers and pass traffic back to load bearing servers using ipv4 instead.

It's a classic example of "this is the next best thing everyone should use it" which achieves some adoption but it's not really the next best thing. It's not the be all end all it purports to be.

We should just admit to ourselves that we need one kind of ip stack in some situations and another in another.